Design and Development of Electrostatic Charge Tester for Textile Yarns

Transcription

1 JOURNAL OF APPLIED SCIENCES RESEARCH ISSN: X Published BY AENSI Publication EISSN: X March; 12(3): pages Open Access Journal Design and Development of Electrostatic Charge Tester for Textile Yarns 1 P. Mageshkumar and 2 Dr.T.Ramachandran 1 Assistant Professor, Department of Textile Technology, K.S.Rangasamy College of Technology, India 2 Principal, Karpagam Institute of Technology, India Received 2 February 2016; Accepted 29 February 2016; Published 25 March 2016 Address For Correspondence: P. Mageshkumar, Assistant Professor, Department of Textile Technology, K.S.Rangasamy College of Technology, India mages.kumar@gmail.com Copyright 2016 by authors and American-Eurasian Network for Scientific Information (AENSI Publication). This work is licensed under the Creative Commons Attribution International License (CC BY). ABSTRACT Static problems in textile industry have become more serious as synthetic fibers and higher processing speeds became possible nowadays. A number of instruments are available for measuring static charge accumulation in textile materials. But these can be used to measure in web, fabric, and flat surface forms. Very few instruments are available for measuring staple yarn form. An electrostatic charge tester has been designed to measure the electrostatic charge in the yarn in terms of Volt. The measurements were carried out for nylon, polyester and acrylic yarns with two different relative humidity level, surface speed. It has been found that the measured values for Polyester, Nylon and Acrylic have the decreasing order of static charge accumulation. KEYWORDS: Capacitance loading, Charge tester, hydrophobic fibre, explosion, charge decay, corona charging, static charge, tribocharging, INTRODUCTION Static charge measurements are needed in every stage of textile material manufacturing to show electrostatic conditions that are present, to understand why these conditions are present, to initiate control, and to select or develop suitable yarns. A number of instruments are available for measuring static charge accumulation in textile materials. But these can be used to measure in web, fabric, and flat surface forms. Very few instruments are available for measuring staple yarn form. If it is measured in the yarn formation stage, the problems in downstream processes like weaving; processing, garmenting etc can either be controlled or avoided. But the measurement in yarn stage has following difficulties: The surface area of yarn is very small, which requires very small probe and gives lesser reading The possibility to reach the surface of yarn is difficult because of the mechanical parts of the spinning machine. To alleviate these problems a non contact instrument is developed with easily available, low cost materials Static charge: Generation of static charge in textiles can be explained as tribo electricity which is caused by contact or rubbing operation between two surfaces. Materials can be divided into two types in terms of flow of electric current, conductors and insulators. When two surfaces come into contact, they exchange electrons and get electrically charged. Due to their low surface resistance, conductive materials have high probability of charge exchange, while insulative materials tend to keep electrons because they possess high surface resistance [1]. To Cite This Article: P. Mageshkumar and Dr.T.Ramachandran., Design and Development of Electrostatic Charge Tester for Textile Yarns, Journal of Applied Sciences Research. 12(3); Pages: 14-18

2 15 P. Mageshkumar and Dr.T.Ramachandran 2016/ Journal of Applied Sciences Research. 12(3) March 2016, Pages: Metal and ceramic are good examples of conductor and insulator, respectively. Textile materials are usually defined as semiconductors. They can transfer the electricity like conductors and also can hold electricity like insulators [3].There are two main types of static electricity, volumetric and surface. Volumetric static charges are charge imbalances within the body of a material whereas surface static electricity is only present on the very outer surface of a material. In practice nearly all the static electricity problems found in industry relate to surface charges. Whilst there miss no way of neutralizing volumetric static charges they rarely cause a problem and their effects are normally minimal when compare to surface static charges[7] Static creation: There are three main causes of static electricity. They are friction, separation, and induction. If two materials are rubbed together the electrons associated with the surface atoms on each material come into very close proximity with each other. These surface electrons can be moved from one material to another. A harder the two materials are pressed together the exchange of electrons and hence a higher charge is generated [2]. The method of charging by separation is similar to that of friction. When two materials are in contact the surface electrons are in close proximity to each other and upon separation have a tendency to adhere to one material or the other dependent upon their relative positions on the Turboelectric series. The faster the separation of the materials, the higher charge generated and conversely, the slower the separation the lower the charge [6]. A common example is of a PVC web moving over a Teflon coated roller, as the materials separate the electrons will tend to adhere to the Teflon, generating a net negative charge on the Teflon and a net positive charge on the PVC. Induction does not play a significant role in static charge accumulation. Static charges can be generated when materials are in the presence of a strong electric field. The surface of a material in close proximity to a high positive voltage will tend to become positively charged. Because of the charging caused by ionization of the air between the surface of the material and the voltage source which carried surface electrons away from the material to the source [4] Problems by static charge: In the textile industry, static electricity may cause many problems if it is not kept under control. The problems may be: Uneven Yarn Movement, Yarn Jams, Floating Fibre Stacks, Contamination Problems, Uneven drafting, Dust accumulation, Fly, fluff generation and accumulation, Overloading of electronic equipment and break down Static discharge in an operating room may lead to an explosion risk of shock. Increased production time: in some areas very long textile materials are produced. Because of the static charge on it, roll should be used for some time to allow static charge dissipation. Fibre breakage and decreased fabric strength: spun bond machine during production, before transferring the web to calendar bonding, the fabric sticks to the belt. This may cause fabric breaks during production and higher process time. MATERIALS AND METHODS Extensive research has been done in this field. However, there are still questions not answered, and drawback. For example, the accuracy of the measurement is questionable due to the manual transfer of samples to the measuring unit, the devices and procedures are complicated and the results are not reproducible in electrostatic charge Electrostatic Sensor: Double-layer film sensor for the measurement of forces is presented. The sensor is a thin film (thickness below 1 mm) based on a sandwich structure composed of two sensing elements glued together: one layer is a capacitive film and the other is a piezoelectric film. Both the layers are sensitive to compression loads, but they are suitable for working in different frequency ranges. In fact, while the capacitive element is capable of measuring DC up to about 400 Hz, on the contrary, the piezoelectric film works in the high frequency range. The output signals of both the sensors are acquired and then filtered and processed in order to achieve a single output signal. The piezo capacitive sensor has been developed in order to synthesize, in a small and cheap device, the capability to measure compression forces in a wide range of frequencies. In particular, the very small

3 16 P. Mageshkumar and Dr.T.Ramachandran 2016/ Journal of Applied Sciences Research. 12(3) March 2016, Pages: thickness allows inserting it into a composite material to measure actual loads and excitations, as well as on the surface or between different components of a more complex system in order to obtain a smart structure Block Diagram for Electrostatic Charge Tester: 2.3. Operational Amplifier: It consists of two independent, high gain, internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltage. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage Ananlog To Digital Converters: Modern high resolution analog-to-digital converters (ADCs) usually require input buffer amplifiers (ADC drivers), because they often present a dc load of several hundred ohms or more and a high frequency dynamic load to the source that is driving them. If the source is a transducer or a typical low frequency preamplifier, significant errors may occur.the ADC driver is a high performance fast-settling op amp with input impedance of (at least) several mega ohms and a low impedance output circuit which is capable of driving dynamic loads with minimal errors. In addition to buffering, the driver can also provide input scaling (gain) and low-pass filtering to reduce system noise. Some designs can also translate from single-ended sources to differential-input ADCs.In order for the ADC driver to maintain system accuracy, its settling time, noise, and total harmonic distortion (THD) must be considerably better than that of the ADC itself. This is a significant challenge for the designer in systems employing fast 16 - or 18-bit successive approximation (SAR-type) A/D converters Microcontroller: A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals.program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM. Liquid Crystal Display A liquid crystal display (LCD) is a thin, flat electronic display which uses light modulating properties of liquid crystals (LCs). LCs used do not emit light directly. LCD is more energy efficient and offer better disposal than CRTs. Its low electrical power consumption enables it to be used in battery-powered electronic equipments Aluminum foil: The aluminum foil has been used as shied against stray charges around sensor probe and circuits. The static charge built up in the area surrounding to yarn and measuring part will induce stray emf on the area surrounding to yarn and measuring part will induce stray emf on the electronic cirucits. By providing aluminum shield other than the probe will act as a filter and shield to the elctronic circits, there the stray effect will be nullified and the exact measurmet is achievable. To make proper shielding the following materials can also be used: Silver foil or mesh- very costly-very good shield Copper foil or mesh- costly- very good shield- oxidation will be more with ambient conditions Aluminum foild and mes- low cost- easy to get- moderate sheld In this instrument, aluminum foil cover by polyethylen layer is used and it is grounded with commn ground of measuring unit 2.7. Circuit Diagram:

4 17 P. Mageshkumar and Dr.T.Ramachandran 2016/ Journal of Applied Sciences Research. 12(3) March 2016, Pages: The above parts are connected as per the cirucit plan. RESULTS AND DISCUSSIONS The designed instrument is used to measure the static volt in yarn at ring frame. The tests were conducted with the following variables viz. Linear density-ne 40 S, Temperature- 30ºC, RH- 45% The results obtained are as follows. Table 1: Effect of surface speed on static charge generation in yarns at 45% RH. Surface speed (m/min) Nylon yarn (Volt) Polyester yarn (Volt) Acrylic yarn (Volt) Fig. 1: Effect of surface speed on static charge generation in yarns at 45% RH. Another measurement was taken with same parameters but a different RH% Linear density-ne 40 S, Temperature- 30ºC, RH- 65% The results obtained are as follows. Table 2: Effect of speed on static charge generation in yarns at 60% RH. Surface speed (m/min) Nylon yarn (Volt) Polyester yarn (Volt) Acrylic yarn (Volt) Acrylic yarn (Volt) Polyester yarn (Volt) Nylon yarn (Volt)

5 18 P. Mageshkumar and Dr.T.Ramachandran 2016/ Journal of Applied Sciences Research. 12(3) March 2016, Pages: Fig. 2: Effect of speed on static charge generation in yarns at 60% RH. Influence of surface speed on potential values at temperature 30ºC with two Relative Humidity 45% and 65% is shown in table 3.1 and 3.2. It is found that the speed had significantly influenced the electrostatic charge. When speed is at 30 mpm the charges produced are less for all three different yarn. If speed increases the charge produced also increases at both RH levels. This may be due to the higher rate of friction and seperation. The static charge accumulation is high for polyester yarn among the selected three yarn. It is may be due to polyester has very less moisture regain value of 0.4%, and it s high crystalininty also paves higher resistance for the charge flow. Nylon has the second highest charge accmulation among the selected three yarns. This is because it s moisture regain value is 4.5% and it has relatively less compact strucure than the polyester. Acrylic yarn shows a peculiar staic charge accumulation, though it has the low moisture regain value of 1.5% it has less chareg accumulation than the nylon. It may be polarity nature of the charge generation. Subsequently at relative humidity is 65% the least static charge values was produced. This may be due to the impact of RH on the moisture content of the fibre. IV. Conclusion: The instrument was designed for measuring static charge accumulation at staple yarn stage, and the static values for three types of yarn Acrylic, Polyester, and Nylon were measured. It is found that the measured static electricity values carry a resemblence with filament yarn values of the same type.the surface speed has the linear relationship with the static charge accumulation and RH% has inverse effect on the same. The measured values for Polyester, Nylon and Acrylic have the decreasing order of static charge accumulation. REFERENCES 1. Seyam, A.F., W. Oxenham, P. Castle, Y. Cai, L. Liu, Static Generation and Control in Textile Systems. Journal of Electrostatics, 40(41): Bailey, A.G., The charging of insulator surfaces. Journal of Electrostatics, 51: Steiger, F.H., Evaluating Antistatic Finishes. Textile Research Journal, 28(9): Chubb, J., New approaches for electrostatic testing of materials.journal of Electrostatics, 54(3): Chubb, J.N., Instrumentation and standards for testing static control materials. Industry Applications, IEEE Transactions on, 26(6): Kacprzyk, R., C. Stec, Measurements of the surface charge density on moving webs. Journal of electrostatics, 40: Slade, P.E., Antistats. Handbook of Fiber Finish Technology, New York, USA, Marcel Dekker, Zaukelies, D.A., An instrument for study of friction and static electrification of yarns. Textile Research Journal, 29(10): Bal, K., V.K. Kothari, Measurement of dielectric properties of textile materials and their applications. Indian Journal of Fibre & Textile Research, 34: Gniotek, K., P. Tokarski, New Methods of Assessing Static and Dynamic Flow Characteristics of Textiles. Textile Research Journal, 70(1): Buhler, C., C. Calle, S. Clements, M. Ritz, J. Starnes, Test methodology to evaluate the safety of materials using spark incendivity.journal of electrostatics, 64(11): Onogi, Y., N. Sugiura, C. Matsuda, Temperature effect on dissipation of triboelectric charge into air from textile surfaces. Textile research journal, 67(1):